Equine incontinentia pigmenti (IP): X-linked ectodermal dysplasia caused by variants in IKBKG (NEMO). Affected mares develop pruritic and exudative skin lesions from birth that progress to verrucous lesions and areas of alopecia, together with lighter and darker coat streaks, and possible dental, nail and ocular abnormalities. Affected males die at the embryonic stage.

Described in Quarter Horse and Warmblood, associated with a high number of spontaneous abortions in affected studs. Limited data.

Pruritic and exudative skin lesions shortly after birth that progress to verrucous lesions and alopecia with regrowth of woolly hair; lighter/darker coat streaks from birth; possible dental, nail and ocular abnormalities. Only manifests in mares.

Towers et al. (2013) described a family of horses with a skin condition compatible with human IP and a heterozygous nonsense variant in IKBKG (c.184C>T; p.Arg62*), homologous to one already described in humans. It is the first large-animal model for IP.

Avoid mating carrier mares; affected males are lost as abortions. Selection should be based on the genotype of the mares.

Differential diagnosis with other ectodermal dysplasias and neonatal dermatopathies. Confirmation is molecular (IKBKG). The laboratory currently catalogs it under 'coat hyperpigmentation'.

1. Towers RE, Murgiano L, Millar DS, et al. A nonsense mutation in the IKBKG gene in mares with incontinentia pigmenti. PLoS One. 2013;8(12):e81625. PMID 24324710; PMCID PMC3852476. 2. OMIA:001899-9796 (Incontinentia pigmenti, horse).